The present invention relates to a foam insulation part for acoustic insulation or sound absorption and preferably as moisture barrier, which can be arranged within a hollow space created by an outer wall and an inner wall of the door of a motor vehicle. The insulation part is profiled and has a wall with a thickness which is approximately the same at all places and is thin as compared with the space between the inner surfaces of the outer and inner walls.
Since a long time ago one has provided moisture barrier in the form of a film in the hollow space of vehicle doors, for instance between the inner and outer plates. In this connection, reference is had, by way of example, to Federal Republic of Germany Utility Model 78 04 040.
Vehicle doors generally consist of an inner metal sheet and an outer sheet which are spaced from each other if only in order to receive the door-opening mechanism and the window crank, as well as the windowpane in the open condition of the window. Furthermore, adjoining it on the inside, there is another wall which is shaped to receive or directly to form an arm rest, a storage space, an ash tray, or the like. In addition to sealing the inside of the vehicle from penetration of moisture from the outside, there is also an increasing desire to obtain effective acoustic insulation and/or sound absorption.
In this connection, Federal Republic of Germany OS 35 10 018 is also known. Here, the insulation part, which also has sound absorption and insulating properties, consists of a foam blank with a foil applied facing the outside of the door, the foil being intended to provide the moisture barrier. The foam blank is so shaped that it lies substantially with its full surface against a metal wall of the door, insofar as holes are not present there. Furthermore, the foam part is relatively thick as compared with the width or thickness of the hollow space in which it is arranged.
Reference is further had to Utility Model 89 09 961. That utility model concerns an insulating part developed with a double wall. There are two layers of the insulating part which rest against each other. Due to the double-layer spaced structure it is as a whole relatively rigid.